Fix Elasticsearch function test

[sebastienros]

Description

Fixes #7452

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Is this introducing a breaking change?
      • Yes
        • Link to aspire-docs issue (please use this breaking-change template):
      • No
        • Link to aspire-docs issue (please use this doc-idea template):
  • No

[sebastienros]

@Mpdreamz does this change make sense? The PingRequest uses "ping" as the OperationName, I assume the otel part of ES is doing this projection to DisplayName?

[stevejgordon]

@sebastienros I'm going to check this on our end. I expected both DisplayName and OperationName to match and be "ping", so there may be a bug in a recent refactoring of the OTel instrumentation in our libraries.

[stevejgordon]

@sebastienros - Having reviewed our changes, I see that this is expected, and this PR LGTM.

Our Transport layer creates a general Activity passing in the HTTP method name, which becomes OperationName and DisplayName (HEAD in this case). We provide a callback to our client library built on top of Transport, which then sets the DisplayName to the logical operation name (ping in this case). As there is no API to change OperationName, we leave that as is. Since OTLP exports using the DisplayName, this is fine.

[davidfowl]

Thanks @stevejgordon !